UTILIZATION OF FISH PROCESSING WASTE AS A SUPPLEMENTAL FEED FOR SUSTAINABLE AQUACULTURE PRACTICES

An island survey conducted by Aquafeed.com LLC in 2014, and commercial fish landings from the Division of Aquatic Resources, Department of Land and Natural Recourses (published 2011) estimated 6,500 tons of fish processing waste (FPW) was being generated from Hawaii's commercial landings each year. The removal of FPW from the fish processing companies is costing upwards of $10,000 per month to dispose. Total catch of fish landed in Hawaii is approximately 60% tuna species and 40% all other fish species. The freshness (low TVN) of the FPW being generated and dumped, suggest that a high quality ingredient for a supplemental feed could be made available for aquaculture feed industry in Hawaii and the Pacific region. The goal of this study was see if we could replace commercial imported fish feed to the islands by generating a simplified semi-moist water stable feed by grinding  and cooking the FPW with the additions of a minimal amounts of ingredients  such as flour and salt. For an initial study tilapia (Oreochromis honorum) were fed one of five diets where a control commercial tilapia feed (35% protein) was replaced with the supplemental FPW feed at 0% (control),  25% FPW, 50% FPW, 75% FPW, or 100% FPW levels. After 8 weeks, fish fed the 25% supplemental FPW feed was significantly superior in weight gain to all the other treatments. The 50% supplemental FPW feed were statistically comparable to the commercial diet in weight gain.

Another 8 week study  comparing 25% supplemental FPW feed to commercial tilapia feed (35% protein) and commercial trout feed (45% protein) resulted in the trout feed significantly superior in weight gain. However, there was no significant difference in weight gain between the 25% supplemental and the commercial tilapia feed.  A third 8 week trial is underway comparing 25% supplemental feed replacement FPW, 50% supplemental feed replacement FPW and commercial 35% tilapia feed.

With the high cost of disposal for fish processing waste in Hawaii and the outer Pacific islands, utilization of this high quality commercial fishery waste product for supplemental feed could enhance small aquaculture  businesses and the local farming industries. Not only would it relieve the land fill/disposal burden for fish processors, FPW is a valuable raw material for the local industries, reducing cost of commercial feeds.